Electrostatic precipitating device



Nov. 17, 1964 A. F. BOLES ELECTROSTATIC PRECIPITATING DEVICE Filed March 26, 1962 ARTHUR E HOLE-S INVENTOR HUEBNER 8 WORRE L Un es .P sfl Q 3,157,479 ELECTRGSTATEC PREClP.. ACTING DEVKZE Arthur F. Boles, 3129 N. Angus, Fresno, Calif. Filed Mar. 26, 1962, Ser. No. 132,415 6 Claims. (Cl. 555-146) The present invention relates to an electrostatic precipitating device for separating and collecting solid and liquid contaminating particles suspended in moving gases. More particularly, the present invention relates to such a precipating device having multi-point positive and negative electrodes which are readily adapted to be operated from a relatively low source of electrical current such as is available in automobiles, trucks, buses and the like. While the present invention will be described in conjunction with the exhausts of such vehicles, it is not restricted to such use. For example, the precipitator of the present invention may be readily adapted to a wide variety of air conditioning devices such as refrigeration units, de-pollenization units, air purification units, and the like.

Electrostatic precipitat ng devices of the Cottrell type have long been employed in furnace smokestacks and in other large industrial installations where a virtually unlimited supply of power for charging the precipitator is available. These precipitators operate on the principle of charging contaminated particles suspended in moving gases by high voltage corona discharges which force these particles from the gas stream to collect on plates of opposite electrical polarity and grounding the particle charges at the collector plates. The Cottrell industrial precipitator provides a plurality of material collecting ducts within which are individually mounted active or discharge electrodes maintained at a unidirectional high voltage. Particle charging is achieved by bombardment of the particles in the carrier gases by the negatively charged gas ions accelerated from the central discharge electrode to the grounded particle collecting electrodes. The negatively charged gas ions are created along with positive ions within the corona or glow region circumscribing the negative discharge electrode and by electrons released from the corona as a result of the impact of positive gas ions returning to the negative electrode. The electrons move from the corona region and become attached to gas molecules to form negative gas ions which move to the grounded positive collector electrodes. During such movement, the negative ions collide with any solid or liquid particles in the carrier gas to impart negative charges thereto forcing the particles against the positive collector electrodes.

While the above system has done much to alleviate the air pollution problem, the largest single contributor to such problem is the exhaust from automobiles and other vehicles employing internal combustion engines. In highly concentrated areas of population, the pollution produced by automobile exhausts has created a serious health problem. The principle of the above described precipitating system has not been readily adapted to automobile exhausts because of the production, installation, and maintenance costs involved. In addition, the electrical power available in standard automobiles has not been sufiicient successfully to power the precipitators as presently designed.

Therefore, it is an object of the present invention to provide an electrostatic precipitator which may be readily adapted to automobile exhausts and other air treating devices not susceptible for use with present precipitating devices.

Another object is to provide an electrostatic precipitator which can be operated from the relatively low power source available in standard automobiles and the like.

Another object is to provide such a precipitator which Patented Nov. 17, 1964 is readily removable for inspection, service or replacement.

Another object is to provide an electrostatic precipitator for automobiles which provides ample storage for precipitated material to extend the intervals between servicing.

Another object is to provide such a precipitator which is readily adapted to precipitate fumes from the engine crankcase through the exhaust system.

Another object is to provide an electrostatic precipitator for automobiles which may be economically manufactured, installed and maintained on automobiles Without extensive modification thereto.

Other objects and advantages of the present invention will become more fully apparent upon reference to the subsequent description in the specification.

In the drawing:

FIG. 1 is a side elevation of an electrostatic precipitator of the present invention adapted to the exhaust system of a standard production automobile, truck, bus or other device utilizing an internal combustion engine.

PEG. 2 is a somewhat enlarged longitudinal vertical section taken centrally of the precipitator of FIG. 1.

FIG. 3 is a further enlarged fragmentary perspective of the precipitator with portions removed for illustrative convenience.

I FIG. 4 is a somewhat enlarged transverse vertical section taken on line 4-4 of FIG. 2.

FIG. 5 is a schematic diagram of the electrical power system for the precipitator of the present invention.

Referring more particularly to the drawing, an electrostatic precipitator embodying the principles of the present invention is indicated generally at it). The precipitator is adapted to be supported, in the instant em bodiment, on the discharge end of a conventional vehicle exhaust pipe 11 having a muffler 12 and connected to an exhaust manifold 14 of an engine 16. The engine also includes a crankcase portion 17 having a breather tube 18 extended upwardly and rearwardly therefrom. The breather tube mounts a bypass conduit 19 which is connected to the CXhaUSt pipe 11 ahead of the mutiler through a conventional venturi orifice to cause a vacuum in the breather tube and crankcase of the engine. In such installation, the fumes from the crankcase are scavenged into the exhaust gases for precipitation therewith in the precipitator 10.

The precipitator it? provides an elongated tubular shell 26 having a forward neck portion 21 of reduced diameter which is adapted to slide easily in circumscribing relation about the discharge end of the exhaust pipe 11. A circular clamp 22 is disposed about the forward neck 21 of the shell rigidly to clamp the precipitator in rearwardly extended relation upon the exhaust pipe 11. The shell also includes a rearward discharge end 23 and a plurality of longitudinally circumferentially spaced apertures 24 closely adjacent thereto. Also, a plurality of radially inwardly directed longitudinally extended flutes S are formed in the shell 20 in diametrically opposed relation to each other.

An elongated tubular positively charged collector electrode 27, preferably of expanded metallic material and having forwardly and rearwardly opening ends 23 and 29, respectively, is slidably tightly receivable and is frictionally held within the shell 29 upon the flutes 25. The electrode provides a grid or honey-combed sectioned wall" 30 defining openings 31 therethrough which communicate with a plurality of longitudinally extended passages 32 between the wall and the shell. The wall 34 of the collector electrode provides a rough'textured grid of multi point effect to intensify the electrical stress developedwithin the precipitator, as will be more fully described.

Such increase in electrical stress may also be provided 1 by a smooth wall metal tube having a plurality of perforations therethrough forming inwardly extended rough edges, as may be desired.

' A negatively charged substantially cylindrical discharge electrode 35 having a forwardend 36 and a rearward end 37 is adapted to be concentrically mounted Within the wall 30 of the collector electrode 27. The discharge electrode. provides a core 36 having a pluralityof helically wound support rods 38 mounting a multiplicity of radially extended conductor Wires 39 of conductive material such as brass, copper, or the like providing a multi-point brush'eliect to intensify the available corona glow region about the electrode. The forward end 36 of the discharge electrode is rigidly constrained in suchconcentric relation withrthe collector electrode by an insulator block 44? rigidly mounted therebetween adjacent to the forward end 28 or the collector electrode; From the description so far, 'it will be apparent that-the negative and positive electrodes employed herein provide multiple discharge and collecting points which substantially increase the electrical stresstherebetween as compared to the one or more conventional smooth surface electrodes.

IA high-tension pulse transformer 45 is concentrically mounted within'the rearward end 23 of the shell 29 in coaxial relation to the discharge electrode 35 to provide a unidirectional voltage in the form of a negative charge to the discharge, electrode and a positive charge to the collector electrode 27. mounted adjacent to the rearward end of the shell by an insulator block 46 and at its opposite forward end supports the rearward end 37 of the discharge electrode througli an insulator block 47. The transformer is of a load for spark plug ignition, a transistor 60 is employed in the system as a switch partially to bypass the distributor. The transistor is employed in a primary power line 61 which includes a resistor 6 2-between the battery and the transistor. The base of the transistor is' connected through a resistor 63 to a point of the distributor to provide a triggering circuit providing a pulsating electrical current to the transformer 45. Such pulsating current" i may also be generated by the use of a mechanical vibra- The transformer is slidably i diameter to permit exhaust gases to flow therearound and out the apertures 24 and the discharge end 23 of the shell a and is incapsulated within 'a cover of heat resistant mate- 'rial so as not to b'e detrimentally affected by such flow ofhot gases, 'HoWever, the transformer'is not restricted to such placement; it maybe conveniently carried within j the trunkof an automobile, not'shown, closely adjacent to the exhaust pipe or, in order to retainrthe coaxial unit assembly of the preferred embodiment, it may be connectedtothe forward end 36 of the discharge electrode, 35. In the latter instance, the, exhaust pipe 11 can be bifurcated to bypass theltransformer so as not to require the heat insulation necessary when disposed at the opposite rearward end of the precipitator. The transformer 45 and the collector electrode 27 are grounded to the tubular'sh'ell 20 by its connection with the exhaust pipe 11 to complete the electrical power circuit shown in FIG. 5; A pair of power'input lead wires. 50 and 51 is releasably connected to the rearward end "of, the transformer through a suitable insulated aperture in the shell 20. An outputpower line 52 is extended outwardly of the forward end of the transformer for'co nnectio'n to the core 36 of the discharge electrode 35. A 'ground'line 53 is extended outwardly from the transformer for connection to the shell 26. With the above described arrangement, the electrodes and the transformer are rigidly retractable asa unit from the shell atperiodic intervals V for inspection, service, or'repla'cement of the individual components; I M f Asbest shown in FIG. 5, the electrical circuit for tor, thyratron, neon pulser system, or thelike. Also, a neon indicator lamp, not shown, may be installed adjacent to the rearward end of the shell 20 or any other desired location and connected to the above electrical system for ready determination of 'precipitator operation during servicing checks and by law enforcement oflicers following thevehicle. V v

. Operation The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. With the transformer 45 providing a high-voltage, pulsating, unidirectional, current to the discharge electro'de'35, the multiplicity of dis charge points provided by the wires 38 creates a corona or glow region in circumscribingtrelation to the discharge electrode. The contaminating particles in the exhaust gases passing through the shell 20 are charged for precipitation by the bombardment of'negatively charged gas ions being accelerated from the discharge wires'fifi to the multiplicity of points provided by the sectionedwall 30 of. j the positively charged collector electrode 27. The electrons, while moving to the collector electrode, collide with the solid or liquid particles in the exhaust gas. The particles are thereby negatively charged so as to be forced against the sectioned wall of the collector electrode for storage within the passages 32 between the wall and the shell; The electrostatic'force/on the" negatively charged particles can readily be several hundred times the force of gravity which enables the removal of even the most, minute particles from the carrier gasses flowing through the exhaust pipe l1 and outwardly of the tubular shell 20. When the passages 32 become filled, the electrodes and the transformer are readily retractable asa unit from the shell for cleaning. In addition to the removed particu e 7 late matter the, strong corona produced by the high voltage effect tends to neutralize the smog producing components such as, nitrous oxides, unsaturate hydro-carbons. a

.From the foregoing, it is readily apparent. that the lprecipitator of the present invention is effective to provide substantially complete purification or" the exhaust gases passing therethrough; The negatively charged discharge electrode 35 having a plurality of discharge points in combination'with the grid construction of the positive collector electrode 27 provides a considerably larger and denser electrical field than is possiblewitli the conventional smooth electrodes requiring much higher input 7 V voltages. 'Such construction alsoenables the precipita- .torto be powered from a relatively low power source conventional distributor 'pointmake and break; contacts 1nd1catedat'57 in the. low voltage or groundedlinefidof the battery. In order to prevent'an overload'on the dis-' tributor contacts'which are primarily carrying aheavy conventionally available in standard production vehicles. The transformer and the discharge and collector 'electrodes are easily removable as an integral unitrear wardly' from the tubular shell 20,,for perio dic inspection,service carbon monoxide and,

or replacement of the individual components. The grid l i plete removal of the' collected material therefrom iwithout disassembly from the discharge electrode or from the transformer. As shown in 'FlGfl, the pr'ecipitatoris also readily adapted. topurifycrankca'se fumes fro m the engine alongwith the exhaust gas es withoutrequiring a' separate precipitator on the-engine crankcaseor'a's' in conventional practices providing afreburning cycle I through the intake manifold.

' construction of the positive electrode also enables com- Although the invention has been herein 'shoivn f described in what is conceived to-bejthe'most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An electrostatic precipitating device for an automobile exhaust system comprising a tubular mounting member through which a stream of contaminated gas is adapted to flow, a tubular collector electrode having a perforate wall providing a multiplicity of inwardly extended contact points slidably positioned within said mounting member and being frictionally constrained within the mounting member in circumscribing relation to said stream of gas, a substantially cylindrical discharge electrode providing a multiplicity of outwardly extended discharge points, dielectric means mounted on said collector electrode in radially inwardly extended relation to mount said discharge electrode concentrically within said collector electrode in said stream of gas with said discharge points spaced inwardly from said contact points of the collector electrode, said dielectric mounting means permitting unitary removal of the electrodes from the mounting member, an electrical transformer mounted within said mounting member in coaxial alignment with said dis: charge electrode having electrical conductive connection to said discharge electrode and to said collector electrode, and means having conductive connection to said transformer providing a unidirectional electrical pulsating current thereto.

2. An electrostatic precipitating device comprising a tubular shell having opposite inlet and discharge ends through which a stream of contaminated gas is adapted to flow, means for connecting said inlet end of the shell to a source of such gas, said shell including pairs of diaetrically opposed inwardly longitudinally extended flutes; an elongated tubular collector electrode providing oppositely opening inlet and discharge ends slidably mounted on said flutes within said shell with said inlet end of the collector electrode being disposed adjacent to said inlet end of the shell, and said discharge end of the collector elect-rode'being disposed intermediate said opposite ends of the shell, said collector electrode having a sectional grid-like wall of a predetermined diameter providing a multiplicity of inwardly extended contact points and spaced openings therethrough in circumscribing relation to said stream of gas; said flutes of the shell pro viding a plurality of longitudinally extended passages between the wall of the collector electrode and the shell, and said passages communicating with such stream of gas through said openings in the wall of the collector electrode; a substantially cylindrical discharge electrode having an elongated core and a plurality of radially extended wires of electrical conductive material projecting therefrom providing a multiplicity of discharge points of a diameter substantially less than the diameter of said collector electrode and being of a length substantially equal thereto; first dielectric means mounting said discharge electrode concentrically within said collector electrode in said stream of gas, said electrodes defining a passage for such gas between said discharge points of the discharge electrode and said contact points of the collector electrode; a substantially cylindrical electrical transformer having a cover of heat resistant material and providing electrical conductive connection to said discharge electrode, and to said collector electrode; second dielectric means mounting said transformer adjacent to the discharge end of the shell in longitudinally spaced substantially coaxial relation with said discharge electrode; and means having conductive connections extended through said shell to the transformer providing a unidirectional electrical pulsating current thereto.

3. An electrostatic precipitating device comprising a tubular shell having opposite inlet and discharge ends through which a stream of contaminated gas is adapted to flow, means for mounting said inlet end of the shell on a source of such gas and in communication therewith, said shell including pairs of diametrically opposed inwardly longitudinally extended flutes; an elongated tubular collector electrode providing oppositely opening inlet and discharge ends slidably mounted on said flutes within said shell with said inlet end of the collector electrode being disposed adjacent to said inlet end of the shell, and said discharge end of the collector electrode being disposed intermediate said opposite ends of the shell, said collector electrode having a sectional gridlike wall of a predetermined diameter providing a multiplicity of inwardly extended contact points and spaced openings therethrough in circumscribing relation to said stream or" gas; said flutes of the shell providing a plurality of longitudinally extended passages between the wall of the collector electrode and the shell, and said passages communicating with said stream of gas through said openings in the wall of the collector electrode; a substantially cylindrical discharge electrode having opposite forward and rearward ends, an elongated core, and a plurality of radially extended wires of electrical conductive material projecting from the core providing a multiplicity of discharge points of a diameter substantially less than the diameter of said collector electrode, said discharge electrode being of a length substantially equal to said collector electrode; first dielectric means connected to the forward end of the discharge electrode and mounting the same concentrically within said col lector electrode in said stream of gas, said electrodes defining a passage for such gas between said discharge points of the discharge electrode and said contact points of the collector electrode; a substantially cylindrical electrical transformer having a cover of heat resistant material and providing electrical conductive connection to said discharge electrode, and to said collector electrode, said transformer having opposite forward and rearward ends with said forward end thereof electrically connected to said rearward end of the discharge electrode; second dielectric means connected to said rearward end of the transformer mounting the same on the shell adjacent to the discharge end thereof in longitudinally spaced substantially coaxial relation to said discharge electrode; and means having conductive connections extended through said shell to the transformer providing a unidirectional electrical pulsating current thereto.

4. An electrostatic precipitating device comprising a tubular shell having opposite inlet and discharge ends through which a stream of contaminated gas is adapted to flow, means for connecting said inlet end of the shell to a source of such contaminated gas in coaxial relation thereto, said shell including pairs of diametrically opposed inwardly longitudinally extended flutes; an elongated tubular collector electrode providing oppositely opening inlet and discharge ends slidably mounted on said flutes within said shell with said inlet end of the collector electrode being disposed adjacent to saidinlet end of the shell, and said discharge end of the collector electrode being disposed intermediate said ends of the shell, said collector electrode having a sectional gridlike wall of a predetermined diameter providing a multiplicity of inwardly extended contact points and spaced openings therethrough in circumscribing relation to said stream of gas, said flutes of the shell providing a plurality of longitudinally extended passages between the wall of the collector electrode and the shell, and said passages communicating with such stream of gas through said openings in the wall of the collector electrode; a substantially cylindrical discharge electrode having opposite forward and rearward ends, an elongated core,

and a plurality of radially extended wires of electrical conductive material projecting therefrom providing a multi plicity of discharge points of a diameter substantially v less than the diameter o f said collector electrode, said discharge electrode being 'of a length substantially equal to said collector electrod; firstdielectric means connected to the forward end of the discharge electrode mounting the same concentrically within said collector 5 electrode in said stream of gas, said electrodes defining a passage for such gas between said discharge points'of the discharge electrode and said' contact points of the collector electrode; a substantially cylindrical electrical transformer having a cover of heat resistant material and providing electrical conductive connection to said discharge electrode, and to said collectorelectrode, said transformer having opposite forward and rearward ends with said forward end thereof dielectrically connected to said rearward end of the discharge electrode; second dielectric means connected to said rearward end of the transformer mounting the same on the shell adjacent to the discharge end thereof in longitudinally spaced substantially coaxial relation to said discharge electrode;

and means having conductive connections extended through said shell to the transformer providing a unidirectional electrical pulsating current thereto. 7

5. The combination of a collector electrode for an electrostatic precipitating device comprising an elongated tubular Wall having a sectional grid-like inner surface providing a multiplicity of inwardly extended contact points and spaced openings therethrough; a tubular outer shell adapted to constrain a stream of contaminated gas having pairs of diametrically opposed inwardly] longi-" tudinally extended fiutes said shell 'mounting said collect'or electrode in circumscribing relation to said stream of gas, and defining a plurality: of circumferentially spaced longitudinally extended endwardly opening" pas sages. communicating with such stream of gas through said openings in the wall of the collector electrode; a

substantially cylindrical discharge electrode providing a multiplicity of radially outwardly extended discharge points'concentrically mounted within said collector electrode with said discharge points and said contact points disposed in radially spaced relation to permit the flow 40 points disposed in radially spaced relation to permit the flow of such gas therebetween; means mounted infsaid shell and rigidly connected to the discharge electrode in coaxial relation therewith electrically charging said col-,

lector electrode and 'said discharge electrode to opposite polarity, said multiplicity of discharge points and con- 7 tact points intensifying the electrical'stress between said discharge electrode and said collector electrode whereby contaminants in such stream of gas being collected by the collector electrode are "stcredin' said passages; and dielectric -means interconnecting the collector electrode,

mit their'unitary removal from the'shell. V

6. An electrostatic precipitating device for an auto the discharge electrode and said charging means to' permobile'exhaust system'comprising' a'tubular shell having opposite inlet and dischargeends through which astrear'n of contaminated gas is adapted to'ficw; meansfor con- 'necting said inlet end of the'shell to ,asource of'such gas, said shell including diametrically opposed inwardly longitudinally extended flutes; a tubular collector electrode :6

slidably mounted on said dlu'tes and being frictionally constrained thereon within said-shell and having a sectional grid-like wall in cir cum'scribing relation to said stream',

of gas, said wall providing a multiplicity of inwardly extended contact'points and spaced openings therethrough,

said flutes of the shell providing endwardly opening pas- V s'ages between the wall of the collector electrode and the shell, and said passages communicating with such stream of gas through said openings in the wall of the collector electrode; a substantially cylindrical discharge electrode having an end adjacent to'said inlet'end of the shell and an opposite end, said discharge electrode pro-' viding a multiplicity of radially outwardly extended discharge points; first dielectric means extended'in'interconnecting relation between the electrodes adjacent to said inlet end of the shell mounting saiddischarge electrode concentrically within said collector electrode in said stream of gas with said discharge points spaced inwardly from said contactpoints of the collector electrode to permit the passage of gas therearound; an electrical transformer having electrical conductive connection to said discharge electrode and to 'said collector electrode;- second dielectric means slidably supported in the shell adjacent to its discharge end mounting said transformer in the shell'in longitudinally spaced substantially coaxial relation with saiddischarge electnode; 'third dielectric means coaxially connecting said transformer to said .opposite end of the discharge electrode 50 that said collector electrode, said discharge electrode and said transformer are unitarily removable from said discharge end 1 V of the, shell; andmeans having conductive connections extended through said shell to the transformer providing a unidirectional electrical pulsating current thereto; Y

, References Cited by the Examiner V UNITED STATES PATENTS FOREIG PA ENTS 110,774 10/17 Great Britain.

7 01,007 1731 France. 547,106 3/32 GermanyJ 546,824- ,4/56 Belgium.

850,321 10/60 Great Britain.

GEORGE n. MITGHEIQL, Primary Examiner,

' HERBERTL. MARTIN, ROBERT F. BURNEIT,

- Examiners. 

1. AN ELECTROSTATIC PRECIPITATING DEVICE FOR AN AUTOMOBILE EXHAUST SYSTEM COMPRISING A TUBULAR MOUNTING MEMBER THROUGH WHICH A STREAM OF CONTAMINATED GAS IS ADAPTED TO FLOW, A TUBULAR COLLECTOR ELECTRODE HAVING A PERFORATE WALL PROVIDING A MULTIPLICITY OF INWARDLY EXTENDED CONTACT POINTS LIDABLY POSITIONED WITHIN SAID MOUNTING MEMBER AND BEING FRICTIONALLY CONSTRAINED WITHIN THE MOUNTING MEMBER IN CIRCUMSCRIBING RELATION TO SAID STREAM OF GAS, A SUBSTANTIALLY CYLINDRICAL DISCHARGE ELECTRODE PROVIDING A MULTIPLICITY OF OUTWARDLY EXTENDED DISCHARGE POINTS, DIELECTRIC MEANS MOUNTED ON SAID COLLECTOR ELECTRODE IN RADIALLY INWARDLY EXTENDED RELATION TO MOUNT SAID DISCHARGE ELECTRODE CONCENTRICALLY WITHIN SAID COLLECTOR ELECTRODE IN SAID STREAM OF GAS WITH SAID DISCHARGE POINTS SPACE INWARDLYH FROM SAID CONTACT POINTS OF THE COLLECTOR ELECTRODE, SAID DIELECTRIC MOUNTING MEANS PERMITTING UNITARY REMOIVAL OF THE ELECTRODES FROM THE MOUNTING MEMBER, AN ELECTRICAL TRANSFORMER MOUNTED WITHIN SAID MOUNTING MEMBER IS COAXIAL ALIGNMENT WITH SAID DISCHARGE ELECTRODE HAVING ELECTRICAL CONDUCTIVE CONNECTION TO SAID DISCHARGE ELECTRODE AND TO SAID COLLECTOR ELECTRODE, AND MEANS HAVING CONDUCTIVE CONNECTION TO SAID TRANSFORMER PROVIDING A UNIDIRECTIONAL ELECTRICAL PULSATING CURRENT THERETO. 